(Elk) A Scheme interpreter by Oliver Laumann and Carsten Bormann of the Technical University of Berlin. Elk was designed to be used as a general extension language. New types and primitive procedures can easily be added. It has first-class environments, dynamic-wind, fluid-let, macros, autoloading and a dump. It provides interfaces to Xlib, Xt and various widget sets; dynamic loading of extensions and object files; almost all artificial limitations removed; generational/incremental garbage collector; Unix system call extensions; Records (structures) and bit strings.